On a fan-out-heavy install state.db reached 3.4 GB; 70% of message bytes
belonged to subagent sessions, and every one of those rows was also
indexed into messages_fts_trigram, whose shadow tables are ~2.6x the
text they cover (1,029 MB trigram vs 350 MB standard FTS on that DB).
session_search already hides source='subagent' sessions, so the
substring/CJK index bought nothing for them.
Extend the v29 cron exclusion: the messages_fts_trigram_src view, the
three sync triggers, and both deferred-backfill INSERT...SELECTs now use
one shared predicate (FTS_TRIGRAM_SESSION_SQL / fts_trigram_session_sql)
that skips sessions with source IN ('cron','subagent') or the
$._delegate_from creation marker (children spawned under a gateway turn
inherit the gateway's source). Compression/branch continuations carry
parent_session_id without the marker and stay indexed. Child rows remain
canonical in `messages` and fully indexed in the standard messages_fts
word index; explicit source_filter=['subagent'] CJK searches route to
LIKE like cron already did.
The v29 migration gate becomes `< 30` and reuses the same view-swap +
admitted rebuild, so existing installs purge historical child postings
once on open. Fresh DB with 2,000 x 2 KB child messages: 22.4 MB ->
12.5 MB (trigram shadow 10.09 MB -> 0.02 MB).
2b55ded1ac